The present invention pertains to vitrectomy probes, systems, and methods. More particularly, but not by way of limitation, the present invention pertains to control of vitrectomy probes, systems, and methods.
Microsurgical procedures frequently require precision cutting and/or removing various body tissues. For example, certain ophthalmic surgical procedures require cutting and removing portions of the vitreous humor, a transparent jelly-like material that fills the posterior segment of the eye. The vitreous humor, or vitreous, is composed of numerous microscopic fibrils that are often attached to the retina. Therefore, cutting and removing the vitreous must be done with great care to avoid traction on the retina, the separation of the retina from the choroid, a retinal tear, or, in the worst case, cutting and removal of the retina itself. In particular, delicate operations such as mobile tissue management (e.g. cutting and removal of vitreous near a detached portion of the retina or a retinal tear), vitreous base dissection, and cutting and removal of membranes are particularly difficult.
The use of microsurgical cutting probes in posterior segment ophthalmic surgery is well known. These cutting probes typically include a hollow outer cutting member, a hollow inner cutting member arranged coaxially with and movably disposed within the hollow outer cutting member, and a port extending radially through the outer cutting member near the distal end thereof. Vitreous humor and/or membranes are aspirated into the open port, and the inner member is actuated, closing the port. Upon the closing of the port, cutting surfaces on both the inner and outer cutting members cooperate to cut the vitreous and/or membranes, and the cut tissue is then aspirated away through the inner cutting member.
One complication arising during vitrectomy procedures is retinal traction. High traction forces may lead to complications such as retinal tears and retinal detachments. One method that has been used to reduce vitreous traction is the use of increased cut rates. While utilizing these higher cut rates has reduced the average and peak traction, it appears that between cuts the residual traction remains higher than at lower cut rates. It is believed that this is due to the reduction of port closed time between cuts that has occurred with higher cut rates. With the very short time that the port is closed between cuts, the vitreous fibrils do not have a chance to retract and withdraw from the field of influence at the port.
The present disclosure is directed to addressing one or more of the deficiencies in the prior art.